Process of heat treatment



Jun 26, 1923.

E. STANSFIELD PROCESS OF HEAT TREATMENT Filed April 5, 1920 jiwmlbr 76,.

Patented June 26, 1923.

entree STATES,

PA NT OFFICE.

EDGAR STANSFIEL D, OF OTTAWA, ONTARIO, CANADA.

PROCESS OF HEAT TREATMENT.

Application filed April 3, 1920. Serial No. 371,1 88;

To all whom it may concern:

Be it known that I, EDGAR STANSFIELD, a subject of the King of Great Britain and Ireland, residing at Ottawa, in the Province of Ontario, Dominion of Canada, have invented new and useful Improvements in the I Processes of Heat Treatment, of which the following is a specification.

This invention relates to the process of heat treatment of materials and more particularly to the prms of heat treating or carbonizing'coal, lignite, peat, or other car bonaceous material, and has for its object to provide a continuous process in which the material is uniformly heated tothe desired temperature, with greater rapidity than, by

former methods. 7

A further object is to rovide a process by which the gases given 0 at various temperatures can be withdrawn separately, and kept free from contact with heated-surfaces which might cause secondary decomposition.

The process consists in feeding carbonaceous material on to the heated floor of a retort in a thin layer at the cooler end, allowing or causing it to pass througlr zones of increasing temperature, and withdrawing it from the other end, the gases and'vapours produced bein drawn off from above the material, and t e treatment bein controlled by the rate 'of passage through t e retort of the material treated.

By means of this process all the material is thoroughly treated at a succession of increasing temperatures, and the gases given of at the different temperatures are 1m-' mediately withdrawn and can be separated and kept distinct and used for separate purposes.

Inthe methods hitherto adopted the material has usually been treated in the mass. The heat applied had to penetrate thick layers to eflect carbonization, and the wall temperatures had to be carefully regulated to avoid overheating the material adjacent to the heated wall. 7 This necessitated a" longer period of treatment. The gases produced at different temperatures became mixed, and were liable to be exposed to highly heated surfaces whereby secondary decom osition took place.

6 Particular m thod that I have emv ployed is now described. a

The material. to be treated crushed, is subjected in a thin layer toa gradually increasing, temperature on the suitably floor of an inclined retort, along which it descends by gravity and on whlch a continuous mixing and agitation is obtained by means of suitable battles, whereby every particle of the material under oes the same treatment and a uniform pr uct is obtained at the lower end of the retort.

p The gases produced escape freely from the surface of the thin layer of heated material and pass out of the retort without being exposed to heated surfaces liable to produce cracking or further decomposition.

The withdrawal of the treated material from the lower end of the retort can be either continuous or intermittent, and is accomplished by means of suitable mechanism.

The period' of treatment of the material in the retort is controlled bythe speed of withdrawal. This period varies with results deF sired and with quality of material.

By reason of the rapid movement of the material through the retort and the thorough I -mixing effected by its repeated passage under baffles, high floor temperatures can be employed in the lower end of the retort without overheating the-charge.

I have found that the deslred results are obtained when the material travels in very thin layers when cool' and in gradually thickening layers as it attains higher tempera-- tures; This causes a'slower advance through The inclined floor M is ,made of suitable heat resistin material of good thermal conductivity. arborundum slabs are preferred for high temperatures and cast iron plate for lower temperatures. This floor is inclined at an angle eater than that of reposeof the materia Itis heated from below, and is shown as being heated by the gas or'oil burner J inthe combustion chamber H at the'bottom of the-combustion flue K.

The air forthe burner is shown entering atFand "is preferably preheated in the flue,-;,

, rated from 1t by the floor N.

G which is just below the flue K and sepa- ,The products of combustion escapefrom K The retort or gas chamber floor M has a gas-tight cover 0 covered by a layer of heat insulation This chamber may be divided into separate compartments B. B B 'B. with separate gas outlets E. E. At the top of the retort is a [feed hopper A and at the bottom is a chute C from which the-material is with B above the drawn by suitable-im m :By' varying th amount of clearance anjd Having to increase in thickness, and to *The baflies D} are arranged to cross retort vertically and are shown sup f the floor M bythe e'ndplatesR with a} W 5 8 h efiiesand the floor.

adjust the thickness of the layer of charge to meet varying conditions and to treat materials of different composition and quality. By dividing the floor into two oimore parallelchannels as shownin Figs. 2 and? it is possible tolocalize any slip in the charge, thereby ensuring a more equalizedv evolution ofgas in the retort. now describedmy invention what I claim is: j

1. The process of heat treatment of moisture containing carbonaceous material which consists in drylng and comminuting it, passing it, by gravity, in narrow streams, inclined at a greater angle to the horizontajlf than the angle of repose of the material, in

the absence of air and with the agitation induced by its own motion, causing the layer be subjected from below to heat sufficient to remove volatilesubstances from it, which heat increases in temperature as the material moves downward, and withdrawing-the volatiles at se lected points along the path of the material withoutisubjecting fthm tocontact d' rectl-y heated lsurfaceslf- 1 p 2. The process ofiheat" treatment of mo s-- ture containing carbonaceous material which consists in drying and comminuting it, pass ing it, by gravity, in narrow streams," inclined ata greater angle to the horizontal than ,the angle of reposeof the material, in the absence of air and with the a itat-ion" induced byiitsownmotion, causing t e layer to increase in thickness, and to be subjected from below to heat sufficient to remove vola-ftile substances from'it, which heat increases; in temperature as the material moves down 7 .ward, and withdrawing thevolatiles without consists in drying and comminuting it, pass-' ing it, by gravity, in narrow streams, in-

7 than the gngle of repose of the subjecting them to contact 'w i thf. ;di re t 1y heated surfaces.

' 3. The proces of heat treatment of moisture contalning carbonaceous materialmhich clined at a -greater angle to the horizontal material,

through L. to -increase ia mindless;

i trom ba sa which is also im is.

to, the horizontal v ot-[the materi'a the frequency of the" baflies it is possibleto in the absence of air and with'agitation induced by its o wn motion causing the layer "and to be subjected H heat sufficient to remove volatile *subs tanc'esfrom it, which heat increases intemperatureasjh material moves downward; arid "withdrawing the volatiles, without subjecting them to contact with directly heated surfaces, and controllingthe time of treatment by means of the rate of withj drawal of the treated material. rises, -.fi-l sattreetm t at cont m ne arlqonac dus material which s n i y aandlw min n ap s ey's 'yJ fi l iwd a ea r-a le than 5 the a ngleaof repose A V absence of air and with agitation" nduced by its own motion, causing the layer to increase in thickness and to be subjected from below to heat suflicient to remove volatile: substances from it, which heatj increases j I rial I ves do ,nward,and-withdrawing the volatiles without subjecting them topon'tact. w th direq th ta 'sur w l If"; S' @hemsamenwt m s was containing carbonaceous material which consists in drying and comminuting it, pass ing it, by gravity, in .narrowstreams, inclined at a reater angle to the horizontal han. h angt oft mse o the m eri l, n-

.gtem'peraturzeas the mate th b ln eii fiai ii i S'Wit 'ag j c 15y .motion, and to sub: ected f In belo V, 0 heat sufiicienttoremove volatile jces' fromda which Heat in-- creases in .emprature as the material \moves downward, and withdrawing the volatiles at selected points along the path of the material without subjecting them to contact with-v directly heated surfaces.

6. The pnocess of heat treatment of moisntainin cab alby i l l l yiv narrow streams w l s iar" s eata ng iQ- ahqriz than heangle of repose of the material i the absence of air and with agitation, causing the layer [to be and to be subjected from below to heat sufs ficijent to remove. volatilesubstances from it,

which htatiinerease I ma a1 7, moves Ifdownwand, and withdrawe 'yolatileswi'thout subjecting them to t qq fia sf e i l f r ts'l n drying. andis min ssit, pa s-1,

ntal,

increased in thickness s in temperature "as the Y withijdirectly heated surfaces. l

atiles without subjecting them to contact with directly heated surfaces.

8. The process of heat treatment of carbonaceous material which consists in comminuting it, passing .it, by gravity, in streams, inclined at a greater angle tothe horizontal than the angle of repose of the material, in the absence of air, causing the layer to increase in thickness, and to be subjected from below to heat sufiicient to remove volatile substances from it, which heat increases in temperature as the material moves downward, and withdrawing the volatiles without subjecting them to contact with directly heated surfaces, and control ling the time of treatment by means of the rate of withdrawal of the treated material.

9. The process of heat treatment of carbonaceous material which consists in comminuting it, passing it, by gravity, in the absence of air, causing the layer to increase the horizontal than the angle of repose of the material, in the absence of air and with agitation, causing the layer to be increased in thickness and to be subjected from below to heat sufiicient to remove volatile substances from it, which heat increases in temperature as the material moves downward, and controlling the time of treatment by means of the rate of withdrawal of the treated material.

Signed at Montreal, this day of March, 1920.

EDGAR STANSFIELD.

twenty-fourth 

